Portable data carriers with microprocessor control are known in the art. One such device is disclosed in U.S. Pat. No. 4,211,914, to Drexler, issued Aug. 8, 1980. This patent discloses a secure data storage system using both magnetic and optically encoded data on a card. The reference illustrates the use of a microprocessor and read only memory to evaluate the character of the data after a data transaction and is particularly directed to error recognition in data which is to be stored. This is unlike the present invention, which utilizes an optically scanned memory to enhance the data capacity of discrete memory devices of a computer system as well as to decrease the response time of the system. The memory capacity and response time of a computer system are enhanced by the present invention by replacing or extending such discrete memory.
In addition, cards for retention or revision of data in a remote data acquisition system are also known in the art. One such data card is disclosed in U.S. Pat. No. 3,978,320 to McBride, Jr., wherein a card capable of being read by a magnetic card reader is used for displaying and updating inventory data. Unlike the present invention which utilizes an optical laser scanner, this reference discloses an electro-magnetic data accessing system which includes a card reader and card holding matrix to access data. McBride does not utilize a data storage function to replace or extend the capacity of discrete memory devices of a computer system, as does the present invention. Further, the McBride device does not decrease the response time of the computer system.
Several prior art systems for laser optical encoding of plates or strips of optical mediums have been presented in the general field of memory recording mediums. The read/write laser optical card system and related technology utilized in the present invention is well known in the art, as exemplified by U.S. Pat. Nos. 4,360,728 and 4,314,260 to Drexler, entitled Banking Card for Automatic Teller Machines and the Like, and Laser Pyrographic Reflective Recording Layer in a Carbon Containing Absorptive Matrix, respectively.
The '728 patent discloses a data card with a pair of spaced information records. One record is a strip of high resolution reflective laser recording material. The other information record is of a magnetic recording material. An external card "reader" is needed to examine data on the information records or strips and to make additions to the "read-after-write" laser strip contained on the card. The reflective laser recording material is perforated by the laser to encode data on the card or read the data from the card. This external card must be introduced into a remote data card reader/writer for verification, modification or rejection of existing data on the card. This disclosure is particularly applicable to user/card identification applications. The '260 patent discloses a Laser Pyrographic Reflective Recording Layer utilizing a rotating disk for fast random access to the information stored on the layer. Further, the '260 patent discloses the use of stacked plates for intermediate speed random access via an electro-optical scanner. The disclosure of Drexler '728 and '260 is hereby expressly incorporated by reference.
The present invention utilizes the advantages of the laser pyrographic reflective recording layer as disclosed in U.S. Pat. No. 4,314,260 to provide a very high density data medium coupled with a remote data card as disclosed in U.S. Pat. No. 4,360,728 to configure an optical laser card data storage system. The optically encoded memory system is an extension of the random access memory portion of a computer system's architecture due to its ability to rapidly write and read computer information to and from the data card. Further, the memory system of the present invention extends the capacity of the computer's discrete random access memory without changing its characteristics. An optical laser scanner coupled with virtual memory techniques and hardware, as used in the present invention, provides rapid data searching, resembling true read/write semiconductor random access memories.
Semiconductor random access memories have heretofore not been compatible with a variety of multiple processor architectures, particularly hand-held portable architectures, due to physical space requirements. Previously, serial configurations in memory systems would cause major wait states while writing to or reading from the read/write optical laser memory. This occurred when the required computer information was not available in the bit slice processor via the cache memory at the required time because the desired computer information was at the extremities of the optical strip; i.e. the farthest geographic location from the nominal position of the optical reader.
Accordingly, the present invention increases the read/write speed of a computer system by including a virtual memory configuration having a bit slice processor which is in communication with a main processor via a processor bus and an input/output bus. This type of configuration significantly accelerates the retrieval time of the sytem allowing computer information to be available for use by the main processor in a timely fashion. Utilization of an optical laser scanned medium with virtual memory techniques offers a significant improvement in the area of available "on board" active memory providing reduced physical size of the system, while decreasing the accessing time of such a system. Moreover, the use of a multiple processor architecture, in combination with this type of memory medium, brings large scale performance to moderate size geometries and price structures, previously not available in the computer market.